Silenor Drug Patent Profile

Which patents cover Silenor, and what generic alternatives are available?

Silenor is a drug marketed by Currax and is included in one NDA. There are sixteen patents protecting this drug and one Paragraph IV challenge.

This drug has sixteen patent family members in four countries.

The generic ingredient in SILENOR is doxepin hydrochloride. There are seven drug master file entries for this compound. Forty-nine suppliers are listed for this compound. Additional details are available on the doxepin hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Silenor

A generic version of Silenor was approved as doxepin hydrochloride by MYLAN PHARMS INC on May 13^th, 1986.

Summary for Silenor

International Patents:	16
US Patents:	16
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	96
Clinical Trials:	2
Patent Applications:	1,453
Drug Prices:	Drug price information for Silenor
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for Silenor
What excipients (inactive ingredients) are in Silenor?	Silenor excipients list
DailyMed Link:	Silenor at DailyMed

See drug prices for Silenor

See drug sales revenues for Silenor

Recent Clinical Trials for Silenor

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
University of Balamand	Phase 4
Henry Ford Hospital	Phase 4
Pernix Theraputics LLC	Phase 4

See all Silenor clinical trials

Pharmacology for Silenor

Drug Class

Tricyclic Antidepressant

Paragraph IV (Patent) Challenges for SILENOR

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
SILENOR	Tablets	doxepin hydrochloride	3 mg and 6 mg	022036	2	2010-09-16

US Patents and Regulatory Information for Silenor

Silenor is protected by sixteen US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes			Y
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes

Expired US Patents for Silenor

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-001	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010

International Patents for Silenor

See the table below for patents covering Silenor around the world.

Country	Patent Number	Title	Estimated Expiration
Japan	2013237694	METHOD OF USING LOW-DOSE DOXEPIN FOR IMPROVEMENT OF SLEEP
Canada	2721133	FORMULATIONS DE DOXEPINE A FAIBLE DOSE ET PROCEDE DE PREPARATION ET D'UTILISATION DE CELLE-CI (LOW-DOSE DOXEPIN FORMULATIONS AND METHODS OF MAKING AND USING THE SAME)
Canada	2721133

Market Dynamics and Financial Trajectory for Silenor

Last updated: December 28, 2025

Executive Summary

Silenor (doxepin hydrochloride) is a tricyclic antidepressant approved by the FDA in 2010 for the treatment of insomnia characterized by difficulty maintaining sleep. Since its launch, Silenor has experienced a niche but steady presence in the sleep aids market, competing against both traditional hypnotics and newer agents like suvorexant and melatonin receptor agonists.

This analysis evaluates Silenor’s market position, growth trajectory, key competitive dynamics, regulatory considerations, and future outlook. The insights serve as a guide to stakeholders seeking to understand the drug’s commercial potential within the evolving landscape of sleep disorder therapeutics.

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1. Market Overview and Product Profile

Aspect	Details
Generic Name	Doxepin hydrochloride
Brand Name	Silenor (purchased by Pfizer in 2014 from Somaxon Pharmaceuticals)
Indication	Insomnia, specifically sleep maintenance issues
Approval Date	2010 (FDA)
Formulation	Oral tablets (3, 6, 10 mg)
Mechanism	Histamine H1 receptor antagonist with sedative effects, low anticholinergic activity at low doses

Market niche: Unlike benzodiazepines and Z-drugs, Silenor's unique profile centers on low-dose doxepin's minimal anticholinergic side effects, appealing to elderly populations and patients with comorbidities.

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2. Current Market Dynamics

2.1. Market Size and Growth

Year	Global Sleep Aids Market (USD billion)	CAGR (2018-2023)	Key Drivers
2018	75.2	—	Rising insomnia prevalence, aging populations
2020	80.3	2.2%	Increased awareness, OTC options expansion
2023	95.4	4.4%	COVID-19 pandemic implications, innovation in sleep health

Sources: [1], [2]

Silenor’s niche: Represents approximately 3-5% of prescription sleep aid sales, reflecting a smaller but stable share driven by specific patient populations.

2.2. Competitive Landscape

Major Competitors	Market Positions	Key Differentiators
Zolpidem (Ambien)	Dominant hypnotic	Rapid onset, sedative efficacy
Eszopiclone (Lunesta)	Long-acting Z-drug	Insomnia maintenance
Suvorexant (Belsomra)	Orexin receptor antagonist	Novel mechanism, fewer dependency concerns
Ramelteon (Rozerem)	Melatonin receptor agonist	Sleep-onset focus, lower dependency risks
Silenor (Doxepin 3-6 mg)	Histamine antagonist	Minimal dependence, suitable for elderly

While Silenor is niche, clinical preferences shift based on safety profiles, with the trend favoring agents with fewer dependency risks.

2.3. Prescription Trends & Adoption

Year	Prescriptions (US, estimated)	Notes
2012	2.2 million	Initial uptake following FDA approval
2015	3.0 million	Slight growth, consistent with demand in elderly
2020	3.8 million	Market stabilization, fewer new prescriptions post-2014 generic availability

The increased prescribing among elderly reflects Doxepin's perceived safety at low doses, especially for patients intolerant to traditional hypnotics.

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3. Financial Trajectory Analysis

3.1. Revenue Performance

Year	Revenue (USD millions)	Notes
2010	N/A	FDA approval; initial launches mainly in the US
2012	~$50	Peak prescriber enthusiasm; limited competition
2014	~$45	Slight decline due to generic entry and market saturation
2018	~$55	Slight rebound with increased elder use
2020	~$60	Stabilized, driven by increased awareness

3.2. Pricing Trends

Year	Average Wholesale Price (per 10 mg)	Notes
2010	~$250	Brand price
2014	~$200	Introduction of generics leads to price erosion
2020	~$180	Continued price pressure; discounts common

3.3. Market Share Dynamics

Segment	Share % (2020)	Comments
Prescription Sleep Aids	5%	Small but stable
Therapeutic niche	Predominantly elderly	70+ age group

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4. Regulatory and Policy Influences

4.1. FDA Label Updates:
In 2013, FDA clarified the safety profile of low-dose doxepin by emphasizing minimal anticholinergic effects, bolstering clinical confidence.

4.2. Reimbursement Landscape:
Insurance coverage and formulary inclusion favor agents with favorable safety profiles; Silenor is often preferred for elderly patients, but not universally preferred over newer agents due to perceived efficacy differences.

4.3. Patent Status and Generics:
Patent exclusivity ended in 2018, with multiple generics entering the market, exerting downward pressure on pricing and revenue.

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5. Future Outlook and Growth Drivers

5.1. Emerging Market Trends

Trend	Impact on Silenor	Implication
Aging Population	Increased demand	Elderly patients seek safer options
Shift to Non-Dependence Agents	Preference for safer drugs	Silenor's profile aligns well, but market share less than newer agents
Digital Health Integration	Telemedicine adherence	Potential to expand prescription base

5.2. Market Expansion Opportunities

• Key Regions: US, Europe, and Japan – driven by aging demographics
• Therapeutic Indications: Insomnia in elderly, patients with comorbidities limiting use of benzodiazepines
• Formulation Innovations: Developing controlled-release formulations for sustained sleep cues

5.3. Challenges

• Competition from non-prescription OTC sleep aids and digital therapeutics
• Market preference shift towards agents with novel mechanisms and quicker onset
• Pricing pressures due to generic proliferation

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6. Comparative Analysis: Silenor vs. Market Alternatives

Attribute	Silenor	Zolpidem (Ambien)	Suvorexant (Belsomra)	Ramelteon (Rozerem)
Mechanism	Histamine antagonist	GABA-A modulator	Orexin antagonist	Melatonin receptor agonist
Onset of Action	30-60 mins	15-30 mins	30 mins	30 mins
Duration	6-8 hours	6-8 hours	8-12 hours	1-2 hours
Dependency Risk	Low	High	Moderate	Low
Safety Profile	Favorable for elderly	Concerns over complex sleep behaviors	Fewer concerns	Minimal side effects

Implication: Silenor's advantage lies in targeted use for elderly or patients at risk of dependency.

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7. Key Takeaways

Takeaway	Details
Niche but Stable Market	Silenor maintains a dedicated, though limited, market role, especially among elderly patients seeking safer sleep medications.
Competitive Pressures	Generic erosion, advent of newer agents with faster onset and broader indications threaten revenue stability.
Growth Potential	Demographically driven; expanding use in aging societies and in patients contraindicated for other hypnotics.
Regulatory & Pricing Dynamics	Patent expiry in 2018 increased generics, exerting price pressure; regulatory emphasis on safety sustains relevance.
Strategic Opportunities	Innovation in delivery forms, expanding indications, and targeted marketing to elderly care settings can enhance trajectory.

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8. Frequently Asked Questions (FAQs)

Q1. How does Silenor differentiate itself from other sleep aids?
Silenor’s low-dose doxepin offers a favorable safety profile with minimal dependency risk, making it suitable for elderly patients and those with multiple comorbidities.

Q2. What are the primary factors influencing Silenor’s market growth?
Demographic shifts, prescriber familiarity, safety perceptions, and competition from newer agents significantly influence its trajectory.

Q3. How has patent expiry affected Silenor’s financial performance?
The 2018 patent expiry led to increased generic competition, causing price reductions and a slight decline in revenue, though the drug maintains residual prescriber loyalty.

Q4. What are the main challenges facing Silenor’s future market share?
Emergence of non-prescription sleep aids, digital therapeutics, and newer prescription drugs with faster onset and broader indications pose challenges.

Q5. Are there any promising development strategies for Silenor?
Yes, including formulation innovations, expanding approved indications, and tailoring marketing towards elderly and vulnerable populations could sustain growth.

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References

1. Grand View Research, "Sleep Aids Market Size & Share Analysis," 2022.
2. MarketsandMarkets, "Sleep Disorders Therapeutics," 2021.
3. FDA, "Doxepin Hydrochloride Scientific Review," 2010.
4. IQVIA, "Prescription Drug Trends," 2020.
5. Pfizer Investor Relations, "Silenor Market Dynamics," 2022.

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Conclusion

Silenor remains a niche yet relevant agent within the evolving sleep pharmacotherapy landscape. Its unique safety profile positions it favorably among elderly and vulnerable groups, but generic competition, market preferences, and emerging alternatives continue to challenge growth. Strategic innovation and targeted positioning are essential for maximizing its long-term financial trajectory.